Interior Mass Research Articles

A novel bionic lotus leaf channel liquid cooling plate for enhanced thermal management of lithium-ion batteries

Battery Thermal Management Systems (BTMS) are pivotal in safeguarding the safety, efficiency, and lifespan of electric vehicles. In this study, we propose a bionic lotus leaf (BLL) channel liquid-cooled plate to mitigate temperature accumulation issues observed during lithium-ion battery (LIB) discharge. The primary objective is to enhance heat dissipation and achieve uniform temperature distribution within LIBs. We investigated the impact of different interior configurations and mass flow rates on individual lithium-ion battery (LIB) temperatures using single-variable analysis. Our findings indicate that higher inlet mass flow rates effectively lower the temperature increase in individual LIBs, albeit at the cost of inducing a significant pressure drop.The optimal parameter combination is determined through orthogonal analysis. Specifically, the channel angle (α) and inlet mass flow rate (M) are found to significantly influence the maximum temperature (Tmax) of LIBs. The number of channels (N) is optimized to enhance temperature distribution and reduce maximum temperature variation (ΔTmax) within LIBs. Furthermore, adjusting the channel width (D) substantially mitigated pressure drop (ΔP) in the BLL channel liquid cooling plate, thereby improving hydraulic pump efficiency. The identified optimal combination (M = 1.0 g s-1, N = 4, D = 2.5 mm, α = 90°) ensures that Tmax remains below 29.732 °C even during a 5C discharge, a critical requirement. Compared to a traditional serpentine channel with equivalent heat transfer area and inlet mass flow, the optimized BLL channel showed a decrease in Tmax by 0.776 °C, ΔTmax reduction by 2.445 °C, and ΔP reduced to only 43.44 % of that in the serpentine channel. The BLL channel proposed in this research can serve as a valuable reference for BTMS.

Thermodynamics of spherically symmetric thin-shell spacetimes

We analyze the thermodynamics of spherically symmetric thin-shell solutions to Einstein’s equations, including solutions with negative interior mass. We show the inclusion of such solutions is essential for the thermodynamic consistency of the system: the maximum energy principle applies when we include an entropy term from the singularity of the negative-mass solutions, in addition to the Bekenstein–Hawking term for the entropy of solutions with positive interior mass. Then, the thermodynamic analysis leads to four distinct thermodynamic phases. We also show that all types of solutions can be either thermodynamically stable or dynamically stable, but only solutions with zero interior mass can be both. Since most of our results are analytic, thin shell models emerge as a useful theoretical paradigm for exploring gravitational thermodynamics. Our results provide an additional argument in support of the assignment of entropy to the singularity of negative-mass Schwarzschild spacetimes, and, consequently, to Penrose’s conjecture about the assignment of entropy to singularities.

Study of Neutron Star in [formula omitted] and [formula omitted] gravity framework with Polytropic Gas Background

This study reformulates f(T) and f(G) gravity for neutron stars using a modified Tolman–Oppenheimer–Volkoff equation. Reconstruction approaches have been developed in the polytropic gas model context assuming that the star’s density is a quadratic, linear, or exponential function of the radius r. Studies have been carried out on the behaviour of modified gravity theories reconstructed through analytical solutions and the assumption of some already valid forms. The evolution of the radial density of the neutron star has been studied in every instance. For f(T) gravity, it is determined that the density of the neutron star increases with radius, which is explainable as a result of accretion surrounding the neutron star. Additionally, as r→∞, the reconstructed models show asymptotic flatness. As a result, it has been hypothesised that the interior mass of the neutron star resembles an ideal fluid, which results in decreased viscosity and lessened internal resistance. This lowers the possibility of collapse for the neutron star.

Imaging faint sources with the extended solar gravitational lens

We consider resolved imaging of faint sources with the solar gravitational lens (SGL) while treating the Sun as an extended gravitating body. We use our new diffraction integral that describes how a spherical electromagnetic wave is modified by the static gravitational field of an extended body, represented by series of multipole moments characterizing its interior mass distribution. Dominated by the solar quadrupole moment, these deviations from spherical symmetry significantly perturb the image that is projected by the Sun into its focal region, especially at solar equatorial latitudes. To study the optical properties of the quadrupole SGL, we develop an approximate solution for the point spread function of such an extended lens. We also derive semianalytical expressions to estimate signal levels from extended targets. With these tools, we study the impact of solar oblateness on imaging with the SGL. Given the small value of the solar quadrupole moment, the majority of the signal photons arriving from an extended target still appear within the image area projected by the monopole lens. However, these photons are scrambled, thus reducing the achievable signal-to-noise ratio during the image recovery process (i.e., deconvolution). We also evaluate the spectral sensitivity for high-resolution remote sensing of exoplanets with the extended SGL. We assess the impact on image quality and demonstrate that despite the adverse effects of the quadrupole moment, the SGL remains uniquely capable of delivering high-resolution imaging and spectroscopy of faint, small, and distant targets, notably terrestrial exoplanets within $\ensuremath{\sim}30--100\text{ }\text{ }\mathrm{parsec}$ from us.

Gravitational inversion for arbitrary surface mass distribution—application to earth's time-variable gravity with topography

SUMMARY The aim of this paper is gravitational inversion, that is, the determination of the mass density distribution of a central body when given the observed external gravitational field that is produced by the mass itself. This inversion for a 3-D mass distribution is known to be grossly non-unique; whereas that for a 2-D mass distribution on a spherical surface is known to be unique. The latter justifies the surface ‘mascon’, or equivalent-water-thickness, solutions when not considering any interior mass transports for the Earth's time-variable gravity as observed by the GRACE satellite. In this paper, using the gravitational multipole formalism cast in the framework of linear Hilbert space with the notion of inner product, we do two things further: (i) we prove mathematically that the 2-D gravitational inversion on an arbitrary surface is unique; and (ii) we derive the algorithm that leads to the unique exact 2-D mass distribution solution, up to a truncated finite spherical harmonic degree. This pertains directly to reaching refined GRACE mascon solutions that account for the actual Earth surface shape including the ellipsoidal figure and the topography. In the process, we also (re)formulate the exact equations, for spherical or arbitrary shape, unifying the formulae that have appeared in the GRACE-relevant literature.

Revisiting Interior Water Mass Responses to Surface Forcing Changes and the Subsequent Effects on Overturning in the Southern Ocean

AbstractTwo coupled climate models, differing primarily in horizontal resolution and treatment of mesoscale eddies, were used to assess the impact of perturbations in wind stress and Antarctic ice sheet (AIS) melting on the Southern Ocean meridional overturning circulation (SO MOC), which plays an important role in global climate regulation. The largest impact is found in the SO MOC lower limb, associated with the formation of Antarctic Bottom Water (AABW), which in both models is enhanced by wind and weakened by AIS meltwater perturbations. Even though both models under the AIS melting perturbation show similar AABW transport reductions of 4–5 Sv (50%–60%), the volume deflation of AABW south of 30°S is four times greater in the higher resolution simulation (−20 vs. −5 Sv). Water mass transformation (WMT) analysis reveals that surface‐forced dense water formation on the Antarctic shelf is absent in the higher resolution and reduced by half in the lower resolution model in response to the increased AIS melting. However, the decline of the AABW volume (and its inter‐model difference) far exceeds the surface‐forced WMT changes alone, which indicates that the divergent model responses arise from interactions between changes in surface forcing and interior mixing processes. This model divergence demonstrates an important source of uncertainty in climate modeling, and indicates that accurate shelf processes together with scenarios accounting for AIS melting are necessary for robust projections of the deep ocean's response to anthropogenic forcing.

Effect of improved atmospheric opacities in modelling sub-Neptunes

Aims. We investigate the impact of updated atmospheric mean opacity input values on modelled transit radius and the distribution of interior layer mass fractions. Methods. We developed and applied a coupled interior-atmosphere model. Our straightforward semi-grey calculation of atmospheric temperature enables us to perform thousands of model realisations in a Monte Carlo approach to address potential degeneracies in interior and atmospheric mass fraction. Our main constraints are planetary mass and radius from which our model infers distributions of the internal structure of exoplanetary classes ranging from Super-Earth to Mini-Neptune. We varied the relative masses of gas, envelope, mantle, and core layers subject to constraints on the bulk density from observations, and investigated the effect of updating atmospheric mean opacities. Results. First, we validate our model output with observed temperature profiles for modern Neptune. We can reproduce the basic features in the middle atmosphere but not the temperature inversion in the upper layers, which is likely because our model lacks aerosol heating. Calculated interiors are generally consistent with modern Neptune. Second, we compare with the well-studied object GJ 1214 b and obtain results that are broadly consistent with previous findings; they suggest correlations between modelled gas, water, and core mass fractions, although these are generally weak. Updating the opacities leads to a change on the order of a few percent in the modelled transit radius. This is comparable in magnitude to the planned accuracy of the PLATO data for planetary radius, suggesting that the opacity update in the model is important to implement.

Dynamics of charged hyperbolically symmetric matter in modified gravity

We have conducted an in-depth investigation of static anisotropic matter configurations surrounded by electromagnetic field and possessing hyperbolically symmetric geometry by examining their physical characteristics in the framework of Palatini version of f(R) gravitational theory. Choosing the comoving coordinates, we define a canonical orthonormal tetrad and obtain the components of stress-energy tensor in locally Minkowskian frame. Working out the Palatini–Maxwell equations and the interior mass function for such a symmetry, it comes out that the energy density appears as a negative quantity which results in the development of a vacuole in the vicinity of the central region of the symmetry depicting that this region cannot be occupied by matter. We have also assessed the hydrostatic equilibrium equation and the source of tidal forces for the symmetry (i.e. Weyl scalar) and the active gravitational mass. Few scalar functions are then obtained out of the orthogonal decomposition of the Riemann curvature tensor and are utilized for the comprehension of physical characteristics of the matter configuration. Certain explicit solutions to the Palatini–Maxwell equations are also rendered with the help of two physical variables acting as generating functions.

Numerical investigation of heat transfer and fluid motion in air inflatable textiles: Effect of thickness, surface emissivity and ambient temperature

Air inflatable textile has attracted increasing attention due to the advantage of light, cheap, environmentally friendly and low thermal conductivity. While its thermal insulation is still not yet well understood since the complex interior heat and mass transfer under various thickness and ambient conditions. In this work, a three-dimensional model was developed to investigate the fluid motion and heat transfer in both air inflatable and fiber-filled textiles. The coupled conduction, convection and radiation were modelled by CFD approach. The experimental and numerical results were compared to verify the proposed model. Good agreements were found with the average difference in surface temperature and heat flux less than 2.54% and 9.95%, respectively. Then the effect of various parameters including thickness, surface emissivity and ambient temperature on heat flux, thermal resistance and fluid flow behavior was further analyzed. The simulated interior velocity and temperature distribution suggested that the higher thickness (≥10 mm) was not favorable for better thermal insulation when the air was adopted as thermal insulation layer. Because more available space for air movement would accelerate thermal convection and result in the deteriorated thermal insulation. In addition, inner surface layer with lower emissivity could effectively suppress the thermal radiation in air inflatable textiles and was beneficial to increase the thermal insulation. Besides, the thermal insulation of fiber-filled textile was nearly unaffected when lower ambient temperature was applied, while that of air inflatable textiles significantly decreased due to the aggravated convective heat and flow transfer under large temperature difference.

Adaptation Of Dutch Colonial Architecture to Palembang's Humid Tropical Climate

The Dutch Colonial Architecture in the Talang Semut Palembang area notes that there is a lot of diversity in the style and function of the building as well as the historical journey that includes the adaptation process. This adaptation process is observed in the design world today and in the future. Proof of the adaptation process is carried out by calculating physical analysis to find out the extent to which this tropical consideration is carried out. The process of adapting Dutch Colonial architecture to a humid tropical climate is expected to be able to provoke the creativity of architects in designing buildings properly without using artificial air conditioning equipment. The arrangement of interior layout, outer space and mass management as well as the environmental pattern of this Dutch residential area with the completion of the detailed construction planned to anticipate tropical problems have really been carried out properly.

Electrochemical Activation of Nickel Oxide Incorporated Aluminum-Zinc Alloy Matrix as an Efficient Sacrificial Anode in Marine Environments

For cathodic protection of steel, the aluminium-zinc alloy sacrificial anodes incorporated with nickel oxide nanoparticles were fabricated. The metallurgical properties of Al-Zn sacrificial anodes enhanced substantially through the infiltration and uniform dispersion of nickel oxide nanoparticles into an Al-Zn matrix. Such effective and uniform presence of nano nickel oxide inside the interior mass of the anodes was characterized by electrochemical techniques. The anodes showed considerably low polarization, steady and high active open circuit potential and substantially decreased self-corrosion during galvanic exposure for prolonged periods. The presence of nickel oxide nanoparticles in the anode matrix caused effective destruction of the passive aluminia film, which facilitated enrichment of galvanic performance of the anode. The anode had high resistance against biofouling also.

Facile Fabrication of Manganese Dioxide Composite Incorporated Aluminium Rich Alloy Metal Matrix as Efficient Sacrificial Anodes

Nanosized manganese dioxide was prepared by anodic electro deposition method under standardized experimental conditions. Aluminum-zinc alloy sacrificial anodes incorporated with MnO2 nanoparticles were fabricated for cathodic protection of steel. The physico-chemical properties of anodes were enhanced by uniform dispersion and infiltration of the nano-MnO2 particles into the Al-Zn matrix. Such effective and uniform presence of nano-MnO2 inside the interior mass of the anodes was characterized by electrochemical techniques. The anodes exhibited stable potential in open circuit, small polarization and significant rate of depletion in self-corrosion in the course of galvanic immersion studies. The existence of nanocomposite particles in the anode matrix caused effective destruction of the passive aluminia film, which facilitated enrichment of galvanic performance of anode. The anode had better endurance against biofouling also.

Hydrothermal catalysis of waste greases into green gasoline, jet, and diesel biofuels in continuous flow supercritical water

AbstractThe production of green gasoline, jet, and diesel biofuels from waste greases was achieved using a novel hydrothermal, continuous‐flow catalytic process operating under supercritical water conditions, with recycled water the only added chemical. Thermally and chemically stable catalysts were explored to optimize yields of liquid biofuels and to minimize production of gases and acidic compounds. A 50:50 mixture of brown and yellow waste greases converted into 76.6 wt% liquid biocrude (BC); the remainder converted to water and gases. Less than 0.2% of the feedstock (FS) formed carbon char (mainly amongst catalyst particles). Various tubular reactors (Inconel, Hastelloy, titanium, stainless) showed no interior defects, erosion, or mass loss after runs. The titanium catalyst was fully recovered and regenerated back to its original potency. The BC was further refined into 28%, 48%, 20%, and 4 wt%, respectively for green gasoline, jet, diesel, and bunker. Biofuels were analyzed for compound class compositions and reaction mechanisms were proposed. Hundreds of identified fuel products (C3‐C35) from processing oleic acid as a pure model compound were identified. The neat green gasoline and diesel biofuels, along with a 50% green jet blend (with petroleum Jet A), were tested in appropriate spark ignition, turbine, and diesel engines at the University of Minnesota Engine Labs. The biofuels achieved 107.7%, 97.2%, and 101.3% engine power performance levels relative to petroleum fuels (91‐Octane, Jet A, #2 Diesel) along with lower CO and pollutant emissions. The biofuels complied with American Society for Testing and Materials (ASTM) fuel specifications (D4814, D7566, D975) including mandated corrosion and low sulfur limits of all three biofuels. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Application of gas phase tracking approach in hydrodynamic simulation for gas–liquid two-phase flow in undulant pipelines

In this paper, we propose a new hydrodynamic model for gas–liquid two-phase flows in undulant pipelines based on the gas tracking method. The motion of three main forms of gas phase, including elongated bubbles, small bubbles, and gas pockets, is modeled by respective momentum equations. The mass transfer behaviors among the three gas forms, including interior mass transfer of single gas form, are considered. Therefore, the flow patterns along the pipeline can be predicted based on the gas tracking method. Afterward, the integrated pressure gradient of the gas–liquid two-phase flow in undulant pipelines can be obtained with the updated flow patterns. The model validation using the field data of a real pipeline in China shows that the accuracy of this model is within acceptable range. According to the simulation results, how the pipe terrain affects the gas transport and flow patterns is revealed, and sensitive analysis is carried out. These findings are of great practical value to obtain a deeper understanding of gas–liquid two-phase flows in undulant pipelines.

On the Impact of 22Ne on the Pulsation Periods of Carbon–Oxygen White Dwarfs with Helium-dominated Atmospheres

Abstract We explore changes in the adiabatic low-order g-mode pulsation periods of 0.526, 0.560, and 0.729 M ⊙ carbon–oxygen white dwarf models with helium-dominated envelopes due to the presence, absence, and enhancement of 22Ne in the interior. The observed g-mode pulsation periods of such white dwarfs are typically given to 6−7 significant figures of precision. Usually white dwarf models without 22Ne are fit to the observed periods and other properties. The rms residuals to the ≃150−400 s low-order g-mode periods are typically in the range of σ rms ≲ 0.3 s, for a fit precision of σ rms/P ≲ 0.3%. We find average relative period shifts of ΔP/P ≃ ±0.5% for the low-order dipole and quadrupole g-mode pulsations within the observed effective temperature window, with the range of ΔP/P depending on the specific g-mode, abundance of 22Ne, effective temperature, and the mass of the white dwarf model. This finding suggests a systematic offset may be present in the fitting process of specific white dwarfs when 22Ne is absent. As part of the fitting processes involves adjusting the composition profiles of a white dwarf model, our study on the impact of 22Ne can provide new inferences on the derived interior mass fraction profiles. We encourage routinely including 22Ne mass fraction profiles, informed by stellar evolution models, to future generations of white dwarf model-fitting processes.

Moho Interface Changes Beneath the Tibetan Plateau Based on GRACE Data

AbstractThe Tibetan Plateau (TP) experiences complex mass transfer and redistribution due to the effects of the internal Earth dynamics and external climate change, such as land water changes, crustal uplift, surface denudation, and Moho interface changes. These phenomena are accompanied by changes in the gravity field and can be observed by the Gravity Recovery and Climate Experiment (GRACE). This study uses GRACE data to estimate the mass changes expressed by the equivalent water height (EWH) anomaly of the TP. In addition, we use ICESat data and hydrological models to estimate the effects of hydrological factors (lakes, glaciers, snow, soil moisture, and groundwater) and to separate them from the comprehensive mass field to obtain the tectonic information. We found that the total hydrological contribution to the average EWH change is −0.27 ± 0.21 cm/yr. We further estimated a mean rate of 0.78 ± 0.06 mm/yr by interpolating the Global Navigation Satellite System (GNSS) velocities. Furthermore, large amounts of sediments have been accumulated on and around the TP because of TP's denudation, and the denudation and sedimentation rate were estimated in our study. By removing the effects of the hydrological changes, surface movements, and glacial isostatic adjustment (GIA) from the GRACE, we obtained the EWH change of 0.18 ± 0.22 cm/yr contributed by the interior mass change. We estimated a mean Moho interface uplift rate of 4.20 ± 5.13 mm/yr, and the distribution of Moho interface changes indicates that the northern TP's Moho interface is upwelling and the southern interface is deepening.

Reserves to increase beef production and their use

The studies were carried out on three groups of superreplacement heifers of the Simmental breed, which were impregnated at the body weight of 360 kg. In the first group there were 32 unimpregnated heifers, in the second – 28 heifers, in the third – 30 heifers. The heifers of the first group after growing at the age of 18 months were taken for meat. 56 heifers gave the crop. The heifers were transferred for reproduction, and the bull-calves were put on cultivation and further fattening. To obtain well-fed animals, special diets were made so that the average daily gain was at least 650-700 g. After calving, the cows of the second group were taken for meat, and the cows of the third group were put on a 3-month fattening, and then taken for meat. The pre-slaughter weight of animals of the first group was 52 kg lower than that of animals of the second group and 104.7 kg lower than that of the third group. The difference was statistically significant at P>0.999. The interior fat mass was higher in the carcasses of cows of the second group by 1.1 and 3.2 kg compared to the animals of the third and first groups. The carcass yield was almost at the same level slightly ahead of the animals of the first group. Their slaughter yield was 60.1%, in other groups – 58.8-59.6%. The meatiness ratio was slightly higher in animals of the first group. The carcass weight of the first-calf heifers of the third group was 27.4 kg higher than that of the second group. Compared to the first group, this figure is higher by 52.6 kg. Specific carcass meat weight of the animals of the third group was 82.75%, which is higher than in the second and first groups by 0.41-0.85%, respectively. Heavy cowbanes weighing 32.6 and 40.4 kg were obtained from the animals. The skin of animals of the third group was 3.5-21.6 dm2 larger in area than of the animals of the second and first groups. Feeder bull-calves (n=27) had a removable mass of 532 kg. Heavy (282.3 kg) carcasses of good morphological composition were obtained from them. The sales revenue from first-calf heifers (second group) was higher than fattened heifers by 10.4%, and in comparison with fattened animals after calving (third group) it was lower by 9.4%. From the sale of one cow with a crop, 2.9 times more profit was received than from the sale of a heifer.

Some results on the internal finite‐time stabilization of vibrating strings with interior mass

In this paper, the problem of internal finite‐time stabilization for 1‐D coupled wave equations with interior point mass is handled. The nonlinear stabilizing feedback law leads, in closed‐loop, to nonlinear evolution equations where Kato theory is used to prove the well‐posedness. In addition, it is showed that in some cases, the solution of this hybrid system is constant in finite‐time if we use Neumann boundary conditions. This result can be improved (in complete finite‐time stability sense) if we change the above feedback.

Stable, thin wall, negative mass bubbles in de Sitter space-time

Negative mass makes perfect physical sense as long as the dominant energy condition is satisfied by the corresponding energy-momentum tensor. Heretofore, only {\it configurations} of negative mass had been found \cite{Belletete:2013nqa,Mbarek:2014ppa}, the analysis did not address stability or dynamics. In this paper, we analyze both of these criteria. We demonstrate the existence of {\it stable}, static, negative mass bubbles in an asymptotically de Sitter space-time. The bubbles are solutions of the Einstein equations and correspond to an interior region of space-time containing a specific mass distribution, separated by a thin wall from the exact, negative mass Schwarzschild-de Sitter space-time in the exterior. We apply the Israel junction conditions at the wall. For the case of an interior corresponding simply to de Sitter space-time with a different cosmological constant from the outside space-time, separated by a thin wall with energy density that is independent of the radius, we find static but unstable solutions which satisfy the dominant energy condition everywhere. The bubbles can collapse through spherically symmetric configurations to the exact, singular, negative mass Schwarzschild-de Sitter solution. Interestingly, this provides a counter-example of the cosmic censorship hypothesis. Alternatively, the junction conditions can be used to give rise to an interior mass distribution that depends on the potential for the radius of the wall. We show that for no choice of the potential, for positive energy density on the wall that is independent of the radius, can we get a solution that is non-singular at the origin. However, if we allow the energy density on the wall to depend on the radius of the bubble, we can find {\it stable}, static, non-singular solutions of negative mass which everywhere satisfy the dominant energy condition.

A Bayesian approach to infer interior mass anomalies from the gravity data of celestial bodies

SUMMARY Inversions of planetary gravity are aimed at constraining the mass distribution within a planet or moon. In many cases, constraints on the interior structure of the planet, such as the depth of density anomalies, must be assumed a priori, to reduce the non-uniqueness inherent in gravity inversions. Here, we propose an alternative approach that embraces the non-uniqueness of gravity inversions and provides a more complete view of related uncertainties. We developed a Transdimensional Hierarchical Bayesian (THB) inversion algorithm that provides an ensemble of mass distribution models compatible with the gravitational field of the body. Using this ensemble of models instead of only one, it is possible to quantify the range of interior parameters that produce a good fit to the gravity acceleration data. To represent the interior structure of the planet or moon, we parametrize mass excess or deficits with point masses. We test this method with synthetic data and, in each test, the algorithm is able to find models that fit the gravity data of the body very well. Three of the target or test models used contain only point mass anomalies. When all the point mass anomalies in the target model produce gravity anomalies of similar magnitudes and the signals from each anomaly are well separated, the algorithm recovers the correct location, number and magnitude of the point mass anomalies. When the gravity acceleration data of a model is produced mostly by a subset of the point mass anomalies in the target model, the algorithm only recovers the dominant anomalies. The fourth target model is composed of spherical caps representing lunar mass concentration (mascons) under major impact basins. The algorithm finds the correct location of the centre of the mascons but fails to find their correct outline or shape. Although the inversion results appear less sharp than the ones obtained by classical inversion methods, our THB algorithm provides an objective way to analyse the interior of planetary bodies that includes epistemic uncertainty.